THE  UNIVERSITY 

OF  ILLINOIS 

LIBRARY 

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A6RI6ULTUBAL 
UWBY 


UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  NO.  241 


COMPARATIVE  EXPENSE  OF 
MECHANICAL  AND  HAND  MILKING 

BY  F.  A.  PEARSON  AND  H.  A.  ROSS 


URBANA,  ILLINOIS,  JANUARY,  1923 


SUMMARY  OF  BULLETIN  No.  241 

Investigations  conducted  by  experiment  stations  and  the  experience 
of  a  large  number  of  dairymen  have  shown  the  practicability  of  mechanical 
milkers  from  the  standpoint  of  their  effect  upon  production,  upon  the 
quality  of  the  milk,  and  upon  the  physical  condition  of  the  cows.  The 
object  of  this  study  was  to  compare  the  expense  of  mechanical  and  hand 
milking  in  herds  of  different  sizes.  Data  were  obtained  from  32  Illinois 
dairy  farms  on  which  860  cows  were  milked  mechanically  and  from  34 
farms  on  which  850  cows  were  milked  by  hand.  The  farms  were,  as  nearly 
as  possible,  comparable  in  respect  to  efficiency  of  management  and  methods 
of  dairying  except  as  to  the  method  of  milking. 

The  average  annual  expense  of  caring  for  a  cow  milked  mechanically 
was  $18.64.  Man  labor  constituted  76.5  percent  of  the  total  expense; 
power,  13.2  percent,  and  mechanical  milker,  10.3  percent. 

The  average  annual  expense  of  caring  for  a  cow  milked  by  hand  was 
$23.44,  or  $4.80  more  than  the  average  expense  of  caring  for  a  cow  milked 
by  machine.  The  labor  requirement  was  133.9  hours  per  cow  per  annum 
for  the  cows  milked  by  hand  as  compared  with  81.5  hours  for  the  cows 
milked  mechanically. 

In  herds  of  less  than  25  cows,  the  average  annual  expense  of  caring 
for  cows  milked  mechanically  was  $20.55  per  cow,  and  in  herds  of  25  cows 
or  more,  $17.49  per  cow.  This  difference  ($3.06)  was  made  up  of  differences 
of  $1.11  in  labor  expense,  $1.31  in  power  expense,  and  $  .64  in  mechanical 
milker  expense  in  favor  of  the  larger  herds.  No  significant  difference  in 
expense  of  hand  milking,  due  to  size  of  herd,  was  found. 

The  average  annual  saving  in  expense  resulting  from  the  use  of  me- 
chanical milkers  was  $3.23  per  cow,  or  $61.69  per  farm,  in  herds  of  less 
than  25  cows.  In  herds  of  25  cows  or  more,  the  saving  was  $5.70  per  cow, 
or  $203.49  per  farm.  These  differences  were  based  upon  a  labor  rate  of 
17.5  cents  per  hour.  When  the  labor  rate  was  varied  from  12  -cents  per 
hour  to  30  cents  per  hour,  the  saving  in  expense  resulting  from  the  use 
of  mechanical  milkers  ranged  from  $  .46  to  $9.55  per  cow  for  the  smaller 
herds  and  from  $2.76  to  $12.37  per  cow  for  the  larger  herds. 

Under  some  circumstances  of  size  of  herd  and  expense  of  labor,  there 
is  sufficient  saving  in  labor  to  make  a  mechanical  milker  a  profitable 
investment. 


COMPARATIVE  EXPENSE  OF 
MECHANICAL  AND  HAND  MILKING 

BY  F.  A.  PEARSON,  ASSISTANT  CHIEF  IN  DAIRY  HUSBANDRY,1  AND 
H.  A.  ROSS,  ASSOCIATE  IN  DAIRY  ECONOMY 

Mechanical  milkers  have  been  in  use  for  a  sufficient  length  of  time 
so  that  their  practicability  may  be  determined  from  the  standpoint  of 
their  effect  upon  production,  upon  the  quality  of  the  milk,  and  upon 
the  physical  condition  of  the  cows.  Investigators  in  general  agree  in 
regard  to  their  conclusions  based  upon  the  experimental  use  of  me- 
chanical milkers.  These  conclusions  may  be  summarized  as  follows: 

(1)  Mechanical  milkers,  when  operated  by  competent  men,  have 
little  or  no  effect  upon  the  production  of  the  cows.  Failure  to  thoroly 
strip  by  hand  following  machine-milking  may  cause  decreased 
production.  (2)  When  teat  cups  are  properly  fitted  and  care  is  ex- 
ercised in  operating  the  milker,  there  is  no  harmful  effect  upon  the 
udder  or  teats.  (3)  Clean  milk,  and  milk  with  a  low  bacterial  count, 
may  be  obtained  when  a  mechanical  milker  is  used,  if  sufficient  care 
is  given  to  cleaning  the  machine. 

Dairymen  and  investigators  are  now  generally  of  the  opinion  that 
the  use  of  mechanical  milkers  in  large  herds  results  in  a  saving  of 
labor.  There  are  available,  however,  few  data  on  the  expense  of 
operation.  It  is  the  object  of  this  study  to  compare  the  expense  of 
mechanical  and  hand  milking  in  herds  of  different  sizes.  The  data 
are,  to  a  large  extent,  presented  in  the  form  of  averages.  It  is 
apparent  that  the  cost  of  mechanical  milking  may  vary  widely  on 
different  farms;  but  for  the  farmer  who  is  thinking  of  buying  a 
milking  machine  this  study  should  indicate  the  probable  saving  in 
labor,  and  by  substituting  his  individual  labor  rate  for  the  one  used, 
he  can  better  estimate  the  relative  economy  of  the  two  methods  of 
milking.  It  should  perhaps  also  be  added,  with  respect  to  the  cost 
of  mechanical  milkers  and  their  repair,  that  alt  ho  the  values  pre- 
sented here  cannot  be  taken  as  an  exact  measure  of  their  cost  at  any 
one  time,  yet  the  difference  between  present  costs  and  the  costs  enter- 
ing into  this  study  is  not  large  enough  to  affect  the  practical  applica- 
tion of  the  data. 

SOURCE  AND  CHARACTER  OF  DATA 

These  data  on  the  expense  of  mechanical  and  handmilking  were 
obtained  from  detailed  cost  accounts  kept  on  66  dairy  farms  in 
Illinois.  These  farms  were  representative  of  the  large  group  of  well- 


JMr.  Pearson  was  with  the  Department  of  Dairy  Husbandry  from  1912  to  1920. 

493 


494 


BULLETIN  No.  241 


[January, 


managed,  modern,  and  practical  dairy  farms  from  which  whole  milk 
is  sold.  They  were,  as  nearly  as  possible,  comparable  in  respect  to 
efficiency  of  management  and  methods  of  dairying,  except  as  to  the 
method  of  milking.  Eight  hundred  fifty  cows  were  maintained  on 
the  34  farms  where  milking  was  done  by  hand,  and  860  cows  on  the 
32  farms  where  mechanical  milkers  were  used.  The  following  types 
of  mechanical  milkers  were  used  on  these  farms:  14  Hinman,  9 
Burrell-Lawrence-Kennedy,  6  Victory,  and  3  Sharpies. 

The  data  here  presented  are  on  the  year  basis,  all  expenses  and  all 
accounts  of  labor  hours  being  annual  averages.  The  records  from 
which  they  were  obtained,  however,  cover  seven  fiscal  years,  1914 
to  1920. 


In  this  study  the  items  of  expense  involved  in  caring  for  cows 
milked  mechanically  have  been  grouped  into  three  divisions:  (1) 
power  expense;  (2)  milker  expense;  and  (3)  labor.  All  the  items 
of  expense  of  maintaining  and  operating  the  engines  furnishing  power 
for  the  milkers  have  been  classed  as  power  expense.  Expenses  directly 
attributable  to  the  milkers  proper  have  been  grouped  in  the  second 
division  as  mechanical  milker  expense.  The  cost  of  labor  required 
in  caring  for  the  cows  and  in  operating  the  mechanical  milkers  con- 
stitutes the  third  division. 

POWER  EXPENSE 

Internal-combustion  engines  were  the  source  of  power  on  all  the 
farms  involved  in  this  study.  Gasoline  was  used  as  fuel  on  most  of 
the  farms,  altho  kerosene  was  used  in  a  few  instances.  Relatively 

TABLE  1. — ANNUAL  POWER  EXPENSE  OP  OPERATING  MECHANICAL  MILKERS  ON 
THIRTY-TWO  FARMS  WITH  860  Cows 


Items  of  expense 

Total  expense 

Percentage  of 
total  expense 

Expense 
per  cow 

Gasoline  and  kerosene  

$1,212.28 

57  2 

$1  41 

Depreciation  on  engines  

452.48 

21.4 

.53 

Repairs  on  engines  

144.88 

6.8 

.17 

Interest  on  engines  .  . 

132.11 

6  2 

.15 

Oil  

101.79 

4  8 

.12 

Batteries  

63.45 

3  0 

.07 

Use  of  buildings  

12.00 

.6 

.01 

Total  power  expense  

$2,118.99 

100.0 

$2.46 

small  engines  were  installed,  as  they  require  less  fuel  than  the  large 
engines,  which  develop  unnecessary  power.  Table  1  shows  the  cost 
of  each  of  the  various  power  items  for  the  entire  group  of  farms 
using  mechanical  milkers.  The  power  expense  includes  gasoline  and 


1983]  COMPARISON  OF  MECHANICAL  AND  HAND  MILKING  495 

kerosene,  depreciation  on  engines,   interest  on  investment,   repairs, 
oil,  batteries,  and  use  of  buildings. 

Gasoline  and  Kerosene. — Fuel  for  the  engines,  by  far  the  largest 
item,  made  up  57.2  percent  of  the  total  power  expense.  The  thirty- 
two  farms  under  consideration  used  6,310  gallons  of  gasoline  and 
361  gallons  of  kerosene.  The  average  amount  of  fuel  required  in 
milking  one  cow  for  one  year  was  7.76  gallons,  which  cost  $1.41. 

The  average  cost  of  the  gasoline  used  on  these  farms  was  a  little 
more  than  18  cents  per  gallon,  but  as  the  price  of  gasoline  is  subject 
to  wide  fluctuation  it  is  interesting  to  note  the  effect  of  lower  and 
of  higher  prices  on  the  power  expense.  At  15  cents  per  gallon,  the 
gasoline  cost  per  cow  would  have  been  decreased  25  cents,  at  20  cents 
it  would  have  been  increased  14  cents,  and  at  25  cents  it  would  have 
been  increased  53  cents. 

Depreciation. — Depreciation  on  the  engines  is  the  second  largest 
item  involved  in  power  expense.  This  charge  for  all  the  farms 
amounted  to  $452.48  annually,  constituting  21.4  percent  of  the  total 
expense.  It  was  calculated  in  the  following  manner: 


Inventory  at  beginning  of  the  year  .  . 
Purchased  during  the  vear  

Number 
of  engines 
..32 
3 

Value 
of  engines 
$2,739.27 
318.21 

Total  

35 

$3,057.48 

Inventory  at  end  of  the  year  

32 

$2,545.00 

Sold  during  the  year  

3 

60.00 

Total  

35 

$2,605.00 

Deoreciation  . 

$    452.48 

If  depreciation  were  based  upon  the  inventory  value  at  the  be- 
ginning of  the  year,  the  rate  would  be  16.5  percent ;  or  if  based  upon 
the  average  of  the  inventories  at  the  beginning  and  end  of  the  year, 
the  rate  would  be  17.1  percent,  indicating  that  about  six  years  is  the 
probable  life  of  the  engines. 

Repairs. — Repairs  on  the  engines,  amounting  to  approximately 
17  cents  per  cow,  made  up  6.8  percent  of  the  total  power  expense. 
The  cost  of  repairs  was  equal  to  5.3  percent  of  the  inventory  value  of 
the  engines  at  the  beginning  of  the  year  and  was  about  one-third  as 
great  as  the  depreciation  charge. 

Interest. — Interest  on  the  investment  was  computed  at  the  rate  of 
5  percent  per  annum  and  was  based  upon  the  average  inventory  value 
of  the  engines.  The  interest  charge  on  the  engines  on  these  thirty-two 
farms  was  equal  to  about  one-third  of  the  interest  charge  on  the  milk- 
ing machines,  and  constituted  6.2  percent  of  the  total  power  expense. 

Oil. — Lubricating  oil  was  used  at  the  rate  of  one  pint  of  oil  to 
three  gallons  of  gasoline  or  kerosene.  The  cost  of  the  oil  was  4.8 


496 


BULLETIN  No.  241 


[January, 


percent  of  the  power  expense  and  was  equal  to  one-twelfth  the  cost 
of  the  gasoline  and  kerosene. 

Batteries. — The  cost  of  batteries  for  the  engines  constituted  3  per- 
cent of  the  total  power  expense.  On  sixteen  of  the  farms,  magnetos 
were  the  source  of  ignition ;  on  the  other  sixteen  farms  169  batteries 
were  used,  averaging  one  battery  for  three  cows. 

Use  of  Buildings. — On  a  few  farms,  engines  were  housed  in  spe- 
cial buildings  and  in  those  cases  a  small  charge  for  their  use  has  been 
included  in  the  cost  figures.  No  charge  is  included  when  the  engines 
were  housed  in  the  cow  barns. 

Total  Power  Expense. — The  total  expense  of  maintaining  and 
operating  the  engines  which  furnished  power  for  the  milkers  was 
$2.46  per  cow.  As  was  pointed  out  in  the  discussion  of  fuel  expense, 
this  amount  will  vary  slightly  with  the  price  of  gasoline. 

MECHANICAL  MILKER  EXPENSE 

Table  2  shows  the  expense,  exclusive  of  the  cost  of  power  and  of 
man  labor,  which  was  incurred  in  milking  the  860  cows  on  the  thirty- 
two  farms  where  mechanical  milkers  were  used.  The  items  include 
depreciation  on  the  milkers,  repairs,  interest  on  investment,  germi- 
cidal  preparations,  and  insurance. 

TABLE  2. — ANNUAL  EXPENSE  OF  MECHANICAL  MILKERS,  OTHER  THAN  POWER  AND 
MAN  LABOR,  ON  THIRTY-TWO  FARMS  WITH  860  Cows 


Items  of  expense 

Total  expense 

Percentage  of 
total  expense 

Expense 
per  cow 

Depreciation  on  milkers   

$739.85 

44  8 

$  .86 

Repairs  on  milkers  

456.70 

27.6 

.53 

Interest  on  milkers  

406.72 

24.6 

.47 

Germicidal  preparations  

38.57 

2.3 

.04 

Insurance  on  milkers  

11.35 

.7 

.02 

Total  mechanical  milker  expense. 

$1,653.19 

100.0 

$1.92 

Depreciation. — Depreciation,  the  largest  item,  was  44.8  percent  of 
the  total  mechanical  milker  expense.  The  inventory  value  of  all  the 
milking  machines  at  the  beginning  of  the  year  was  $8,504.31,  and 
at  the  end  of  the  year,  $7,764.46 ;  a  difference  of  $739.85,  representing 
a  depreciation  of  8.7  percent.  This  depreciation  is  based  upon  the 
cumulative  experience  of  these  thirty-two  farmers,  and  not  upon  an 
arbitrary  rate  of  depreciation. 

Milking  machines  have  been  on  the  market  in  considerable  num- 
bers for  more  than  fifteen  years,  and  had  their  use  been  uninter- 
rupted their  rate  of  depreciation  would  now  be  fairly  well  known. 
The  mechanical  milkers  were  purchased  in  large  numbers  about  1906, 
but  they  generally  proved  unsatisfactory,  and  long  before  the  me- 
chanical parts  were  worn  out  many  farmers  disposed  of  them  because 


1923]  COMPARISON  OF  MECHANICAL  AND  HAND  MILKING  497 

of  the  harmful  effects  upon  udders,  the  insanitary  conditions,  etc. 
These  difficulties  were  due  in  part  to  imperfections  in  the  machines  and 
in  part  to  failure  of  the  dairymen  to  follow  directions,  either  thru  care- 
lessness or  lack  of  mechanical  ability.  Agricultural  experiment  sta- 
tions, farmers,  and  manufacturers,  however,  have  found  many  of  the 
causes  of  the  difficulties  and  the  necessary  remedies  or  precautions. 
Thru  much  publicity  by  bulletins,  farm  papers,  advertisements,  and, 
not  the  least,  by  discussions  between  farmers,  the  knowledge  necessary 
to  operate  the  machines  satisfactorily  became  widely  known.  As  this 
knowledge  became  widespread,  and  as  it  became  more  difficult  to 
secure  labor  during  the  period  of  the  war,  the  installation  of  me- 
chanical milkers  was  greatly  stimulated.  If  the  depreciation  were 
based  upon  the  past  experience  of  the  earlier  years,  when  machines 
were  discarded  after  short  trials,  it  would  represent  a  considerable 
proportion  of  the  initial  cost,  if  not  all  of  it.  In  recent  years  the 
machines  have  been  much  more  satisfactory,  but  they  have  not  been 
in  operation  a  sufficient  length  of  time  for  their  probable  life  to  be 
accurately  estimated. 

Repairs. — The  cost  of  repairs  on  the  milkers  constituted  27.6  per- 
cent of  the  total  milker  expense.  The  repair  expense  was  approxi- 
mately three  times  as  great  for  the  mechanical  milkers  as  for  the 
engines,  and  was  three-fifths  as  large  as  the  depreciation  charge.  It 
is  difficult  to  segregate  with  exactness  the  repairs  and  depreciation, 
as  in  many  cases  the  repairs  represent  replacement  of  parts,  such  as 
hose,  pulsators,  and  cup  linings.  In  this  study  the  replacements  have 
been  classified  as  repairs. 

Interest. — The  interest  charge  for  mechanical  milkers  is  calcu- 
lated at  5  percent  per  annum  on  the  average  inventories  at  the  be- 
ginning and  the  end  of  the  year.  This  constitutes  24.6  percent  of 
the  mechanical  milker  expense  on  the  thirty-two  farms.  The  interest 
charge  varies  with  the  type  of  machine,  as  there  is  considerable 
difference  in  the  purchase  price  of  the  different  types. 

Germicidal  Preparations. — The  cost  of  germicidal  preparations 
used  in  solutions  for  the  immersion  of  the  rubber  parts  of  the  milkers 
amounted  to  4  cents  per  cow.  These  preparations  included  lime,  salt, 
calcium  chlorid,  and  various  commercial  preparations. 

Insurance. — Insurance  was  the  smallest  item  of  the  mechanical 
milker  expense,  being  but  .7  percent  of  the  total  expense. 

Total  Mechanical  Milker  Expense. — All  of  the  items  of  expense 
classified  as  milker  expense  amounted  to  $1.92  per  cow  per  annum. 

AMOUNT  AND  COST  OF  MAN  LABOR 

The  labor  included  in  the  present  study  covers  only  the  man  labor 
generally  classified  as  chores.  It  includes  the  time  consumed  in 


498 


BULLETIN*  No.  241 


milking,  feeding,  cleaning,  and  bedding  the  cows,  and  in  caring  for 
the  mechanical  milker  and  milk  utensils.  It  does  not  include  the  care 
of  young  stock,  the  marketing  of  the  milk,  or  the  hauling  of  feed. 
On  a  few  farms  the  amount  of  labor  devoted  to  each  separate  opera- 
tion— milking,  feeding,  bedding  the  cows,  cleaning  the  milkers,  and 
doing  the  other  chores  about  the  dairy — was  recorded  separately, 
but  this  detail  caused  so  much  clerical  work  on  the  part  of  the 
farmers  that  it  was  discontinued  and  the  chores  were  thereafter  listed 
as  one  item.  Consequently  the  data  do  not  permit  the  separation  of 
the  time  consumed  in  caring  for  the  milking  machines  and  gasoline 
engines  from  that  used  for  the  other  dairy  chores. 

The  cost  of  labor  is  based  upon  the  average  wage  of  farm  labor 
(17.5  cents  per  hour)  for  all  the  farms  considered  ,in  this  study.  The 
labor  cost  constituted  such  a  large  part  of  the  total  expense  that  the 
price  paid  for  labor  was  the  principal  factor  determining  the  economy 
of  mechanical  milking.  The  relation  between  various  labor  rates  and 
the  comparative  expense  of  mechanical  and  hand  milking  is  discussed 
in  detail  on  page  505. 

TABLE  3. — AMOUNT  AND  COST  OF  MAN   LABOR  USED   ANNUALLY  IN  CARING  FOR 
860  Cows  ON  THIRTY-TWO  FARMS  WHERE  MECHANICAL  MILKERS  WERE  USED 


Total  annual 
cost 

Total  number 
of  hours 

Annual  cost 
per  cow 

Number  of 
hours 
per  cow 

Man  labor  

$12,264.75 

70,084.25 

$14.26 

81.5 

Table  3  shows  the  amount  and  cost  of  man  labor  used  in  caring 
for  the  860  cows  on  the  thirty-two  farms  where  milking  machines 
were  used.  The  average  number  of  hours  of  man  labor  per  cow 
was  81.5,  and  the  average  annual  expense  per  cow  was  $14.26. 

TOTAL  EXPENSE  OF  MILKING  WITH  MECHANICAL  MILKERS 

The  total  expense  of  milking  with  mechanical  milkers  is  sum- 
marized in  Table  4.  It  will  be  noted  that  man  labor  constituted  76.5 
percent  of  the  total  expense ;  power,  13.2  percent ;  and  mechanical 
milkers,  10.3  percent.  The  total  expense  per  cow  aggregated  $18.64, 
with  $14.26  for  labor,  $2.46  for  power,  and  $1.92  for  the  mechanical 
milker. 


TABLE  4. — TOTAL  ANNUAL  EXPENSE  OF  CARING  FOR  860  Cows  ON  THIRTY-TWO 
FARMS  WHERE  MECHANICAL  MILKERS  WERE  USED 


Items  of  expense 

Annual 
expense 

Percentage  of 
total  expense 

Annual  ex- 
pense per  cow 

Cost  of  man  labor                            .  . 

$12,264.75 

76  5 

$14  26 

Power  expense  

2,118.99 

13.2 

2.46 

Mechanical  milker  expense  

1,653.19 

10.3 

1.92 

Total  expense  

$16.036.93 

100.0 

$18.64 

1983] 


COMPARISON  OF  MECHANICAL  AND  HAND  MILKING 


499 


EXPENSE  OF  MILKING  BY  HAND 

Records  were  kept  of  the  number  of  hours  and  the  cost  of  man 
labor  used  in  caring  for  850  cows  on  thirty-four  farms  where  the 
milking  was  done  by  hand.  This  labor,  as  on  the  farms  on  which  the 
cows  were  milked  mechanically,  included  the  time  consumed  in  milk- 
ing, feeding,  bedding,  and  cleaning  the  cows,  and  in  caring  for  the 
milk  utensils.  The  labor  used  in  hauling  milk  and  feed  and  in  caring 
for  young  stock  was  not  included. 

The  average  amount  of  labor  required  per  cow,  as  shown  by  Table 
5,  was  133.9  hours,  and  the  average  cost  was  $23.44.  The  labor  rate 
(17.5  cents  per  hour)  here  used  in  determining  the  cost  of  labor  was 
the  same  as  that  used  on  those  farms  where  the  cows  were  milked 
mechanically. 

TABLE  5. — AMOUNT  AND  COST  OF  MAN  LABOR  USED  ANNUALLY  IN  CARING  FOR 
850  Cows  ON  THIRTY-FOUR  FARMS  WHERE  MILKING  WAS  DONE  BY  HAND 


Total  annual 
cost 

Total  number 
of  hours 

Annual  cost 
per  cow 

Number  of 
hours 
per  cow 

Man  labor  

$19,920.29 

113,830.25 

$23.44 

133.9 

COMPARATIVE  EXPENSE  OF  MECHANICAL  AND 
HAND  MILKING 

The  average  amount  of  labor  required  to  care  for  one  cow  for 
one  year  on  the  farms  where  the  milking  was  done  by  hand  was  133.9 
hours,  and  cost  $23.44;  while  on  the  farms  where  machines  were 
used,  an  average  of  only  81.5  hours  was  required,  and  the  cost  was 
$14.26.  Thus,  there  was  a  difference  of  52.4  hours  in  time  and  of 
$9.18  in  expense.  This  saving  in  labor  expense  is  offset,  to  some 
extent,  by  the  other  costs  of  mechanical  milking  classified  as  power 
expense  and  mechanical  milker  expense. 

TABLE  6. — COMPARISON  OF  TOTAL  ANNUAL  EXPENSE  INCURRED  IN  CARING  FOR 

860  Cows  MECHANICALLY  MILKED,  WITH  THAT  INCURRED 

IN  CARING  FOR  850  Cows  MILKED  BY  HAND 


Method  of  milking 

Number  of 
cows 

Total  annual 
expense 

Annual  ex- 
pense per  cow 

Mechanical  milking  

860 

$16,036.93 

$18  64 

Hand  milking  

850 

19,920.29 

23.44 

Table  6  shows  a  comparison  of  the  total  expense  of  mechanical 
and  hand  milking.  On  the  thirty-two  farms  where  mechanical 
milkers  were  used,  the  total  expense  incurred  in  caring  for  one  cow 
for  one  year  was  $18.64,  while  on  the  thirty-four  farms  where  hand 
milking  was  practiced,  the  total  expense  of  caring  for  one  cow  was 


500 


BULLETIN  No.  241 


[January, 


$23.44.     Thus,  there  was  an  average  annual  saving  of  $4.80  per  cow 
which  may  be  attributed  to  the  use  of  mechanical  milkers. 

The  use  of  mechanical  milkers  results  indirectly  in  another  saving 
which  is  more  difficult  to  determine.  During  the  crop  season  the 
number  of  hours  in  the  field  is  limited  somewhat  by  the  time  required 
in  milking,  and  the  longer  time  required  for  hand  milking  results  in 
earlier  stabling  of  the  horses  and  the  consequent  loss  of  their  labor. 
The  importance  of  this  factor  in  determining  the  relative  economy  of 
the  two  methods  of  milking  will  vary,  of  course,  with  the  individual 
dairyman,  and  such  saving  as  may  be  involved  does  not  admit  of 
numerical  expression  on  the  basis  of  the  present  study. 


RELATION  BETWEEN  SIZE  OF  HERD  AND  EXPENSE 
OF  MILKING  WITH  MECHANICAL  MILKERS 

Dairymen  frequently  inquire  as  to  the  size  of  a  herd  necessary  to 
make  economical  the  use  of  a  mechanical  milker.  No  definite  answer 
can  be  given  to  this  question  because  of  varying  conditions  and  labor 
costs  on  different  farms.  The  data  in  this  study  indicate  to  some 
extent,  however,  the  relative  saving  resulting  from  the  use  of 
mechanical  milkers  in  large  and  in  small  herds. 

In  order  to  determine  the  relation  between  the  number  of  cows 
on  the  farms  and  the  expense  of  mechanical  milking,  the  farms  on 
which  mechanical  milkers  were  used  are  divided  into  two  groups. 
In  Group  I  are  classed  seventeen  farms  having  less  than  25  cows 
in  each  herd,  with  a  total  of  325  cows  and  an  average  of  19.1  cows 
per  herd.  Group  II  consists  of  fifteen  farms  with  25  cows  or  more 
in  each  herd,  a  total  of  535  cows,  and  an  average  of  35.7  cows  per 
herd.  The  total  expense  of  mechanical  milking  has  been  here  divided 
into  the  three  classes  (power  expense,  mechanical  milker  expense,  and 
cost  of  labor),  as  was  done  when  all  farms  were  considered  together. 

TABLE  7. — RELATION  BETWEEN  SIZE  OF  HERD  AND  THE  POWER  EXPENSE  OF 
OPERATING  MECHANICAL  MILKERS 


Group  I 

Group  II 

All  herds 

Xumber  of  cows  in  herd 

Less  than  25 

25  or  more 

Number  of  herds    

17 

15 

32 

Total  number  of  cows  

325 

535 

860 

Annual  Expense  per  Cow 


Gasoline  and  kerosene 

$1  89 

$1  12 

$1  41 

Depreciation  on  engines 

78 

37 

53 

Repairs  on  engines  

.21 

.14 

.17 

Interest  on  engines  

17 

.14 

.15 

Oil  

.17 

.09 

.12 

Batteries     .      .                      

.06 

.09 

.07 

Use  of  buildings  

.02 

.01 

Total  power  expense  

$3.28 

$1.97 

$2.46 

1923] 


COMPARISON  OF  MECHANICAL  AND  HAND  MILKING 


501 


RELATION  BETWEEN  SIZE  OF  HERD  AND  POWER  EXPENSE 

As  may  be  seen  from  the  data  in  Table  7,  the  expense  of  power 
per  cow  was  less  for  those  farms  having  more  than  25  cows  to  the 
herd  than  for  those  having  smaller  herds.  The  expense  for  Group  I 
was  $3.28  per  cow,  and  for  Group  II,  $1.97,  a  difference  of  $1.31.  All 
items  classed  as  power  expense,  except  the  two  minor  items  (batteries 
and  use  of  buildings),  were  greater  per  cow  for  the  smaller  herds 
than  for  the  larger.  The  large  difference  between  the  two  groups  in 
the  cost  of  fuel  was  not,  however,  due  entirely  to  the  number  of  cows 
per  herd ;  it  was  due  in  part  to  the  fact  that  a  greater  proportion  of 
kerosene,  which  cost  less  than  gasoline,  was  used  on  the  farms  having 
the  larger  herds.  The  average  amount  of  fuel  per  cow  necessary  to 
operate  the  milkers  for  one  year  was  8.88  gallons  in  Group  I  and 
7.07  gallons  in  Group  II. 

RELATION  BETWEEN  SIZE  OF  HERD  AND  MECHANICAL 
MILKER  EXPENSE 

Table  8  shows  the  relation  between  size  of  herd  and  the  mechanical 
milker  expense  per  cow.  Depreciation  and  interest  may  be  considered 
fixed  expenses,  and  the  expense  per  cow  for  these  items  would  there- 
fore be  expected  to  decrease  as  the  size  of  the  herd  increased.  In  the 

TABLE  8. — RELATION  BETWEEN  SIZE  OF  HERD  AND  THE  EXPENSE  OF  MECHANICAL 
MILKERS,  OTHER  THAN  POWER  EXPENSE  AND  COST  OF  MAN  LABOR 


Group  I 

Group  II 

All  herds 

Number  of  cows  in  herd  

Less  than  25 

25  or  more 

Number  of  herds  

17 

15 

32 

Total  number  of  cows  

325 

535 

860 

Annual  Expense  per  Cow 


Depreciation  on  mechanical  milkers. 
Repairs  on  mechanical  milkers  

$   .92 
.79 

$  .83 
.37 

$  .86 
.53 

Interest  on  mechanical  milkers  

.51 

.45 

.47 

Germicidal  preparations  

.08 

.02 

.04 

Insurance  

.02 

.01 

.02 

Total  mechanical  milker  expense.  . 

$2.32 

$1.68 

$1.92 

present  study,  however,  this  decrease  was  not  so  great  as  would  be 
expected,  because  the  investment  per  farm  was  over  60  percent  greater 
on  those  farms  having  the  larger  herds.  This  greater  investment 
was  due  to  the  use  of  more  expensive  types  of  mechanical  milkers 
rather  than  to  the  needs  of  the  large  herds.  Despite  this  fact,  depre- 
ciation and  interest,  as  well  as  the  other  items  of  mechanical  milker 
expense,  were  greater  per  cow  in  herds  of  less  than  25  cows  than  in 
herds  of  more  than  25  cows.  The  average  annual  expense  per  cow 
was  $2.32  in  the  group  of  smaller  herds  and  $1.68  in  the  group  of 
larger  herds. 


502 


BULLETIN  No.  241 


[January, 


RELATION  BETWEEN  SIZE  OF  HERD  AND  THE  AMOUNT  AND 
COST  OF  MAN  LABOR 

For  the  purpose  of  this  study,  the  labor  of  caring  for  cows  milked 
mechanically  may  roughly  be  divided  into  three  kinds:  (1)  milking; 
(2)  feeding  and  cleaning;  and  (3)  care  of  the  milking  machine.  The 
cost  per  cow  for  the  first  two  labor  items  is  little  affected  by  the 
number  of  cows  in  the  herd.  The  time  required  to  milk  one  cow 
bears  little  or  no  relation  to  the  size  of  the  herd.  The  labor  of  feeding 
and  cleaning  may  be  slightly  less  per  cow  in  large  herds  than  in 
small  herds  because  of  more  efficient  methods  or  better  barn  equip- 
ment, but  any  such  economy  of  time  will  be  slight.  It  is  in  relation 
to  the  third  item  that  saving  of  labor  per  cow  is  affected  by  the  size 
of  the  herd.  Considerable  time  is  required  to  wash,  sterilize,  and 
assemble  the  mechanical  milker,  and  unless  more  milker  units  are 
added,  this  is  practically  constant  whether  fifteen  or  fifty  cows  are 
milked.  For  this  part  of  the  labor,  the  time  per  cow  therefore  de- 
creases rapidly  as  the  size  of  the  herd  increases.  In  this  study,  85.4 
hours  of  man  labor  were  necessary  to  care  for  a  cow  for  one  year  in 
herds  of  less  than  25  cows,  and  79.1  hours  in  herds  of  more  than 
25  cows.  The  difference  in  labor  expense,  as  shown  by  Table  9,  was 
$1.11  per  cow. 

TABLE  9. — RELATION  BETWEEN  SIZE  OF  HERD  AND  THE  AMOUNT  AND  COST  OF 
MAN  LABOR  USED  IN  CARING  FOR  Cows  MILKED  WITH  MECHANICAL  MILKER 


Group  I 

Group  II 

All  herds 

Number  of  cows  in  herd                   .  . 

Less  than  25 

25  or  more 

Number  of  herds  

17 

15 

32 

Total  number  of  cows  

325 

535 

860 

Annual  number  of  hours  per  cow  .  .  . 
Annual  cost  per  cow  

85.4 
$14.95 

79.1 
$13.84 

81.5 
$14.26 

Whether  or  not  this  slight  difference  in  time  (6.3  hours  per  cow) 
was  due  to  the  difference  in  the  size  of  herd,  may  best  be  judged  by 
reference  to  the  data  contained  in  Table  13,  which  shows  how  the 
amount  of  labor  required  to  care  for  a  cow  varied  on  the  different 
farms.  The  variation  in  time  among  the  farms  within  each  group 
was  greater  than  the  difference  between  the  averages  of  the  two 
groups.  However,  on  fifteen  of  the  seventeen  farms  in  Group  I  more 
than  80  hours  of  man  labor  was  required  per  cow,  while  on  only  seven 
of  the  fifteen  farms  in  Group  II  was  the  labor  requirement  greater 
than  80  hours  per  cow.  The  data  are  too  limited  to  permit  any 
definite  conclusions  to  be  drawn  in  regard  to  the  relation  between 
the  size  of  herd  and  the  labor  requirement  of  cows  milked  mechani- 
cally, but  they  indicate  that  the  time  per  cow  decreases  slightly  as  the 
size  of  the  herd  increases. 


1923] 


COMPARISON  OF  MECHANICAL  AND  HAND  MILKING 


503 


RELATION  BETWEEN  SIZE  OF  HERD  AND  TOTAL  EXPENSE  OF 
MILKING  WITH  MECHANICAL  MILKERS 

The  total  annual  expense  of  mechanical  milking  in  herds  of  less 
than  25  cows  was  $20.55  per  cow,  as  shown  by  Table  10.  The  total 
annual  expense  in  herds  of  more  than  25  cows  averaged  14.9  percent 
less,  or  $17.49  per  cow — a  difference  of  $3.06. 

TABLE  10. — RELATION  BETWEEN  SIZE  OF  HERD  AND  TOTAL  EXPENSE  OF  CARING 
FOR  Cows  MILKED  WITH  MECHANICAL  MILKER 


Group  I 

Group  II 

All  herds 

Number  of  cows  in  herd  

Less  than  25 

25  or  more 

Number  of  herds  

17 

15 

32 

Total  number  of  cows  

325 

535 

860 

Annual  Expense  per  Cow 


Cost  of  man  labor  

$14.95 

$13.84 

$14.26 

Power  expense  

3  28 

1  97 

2.46 

Mechanical  milker  expense  

2.32 

1.68 

1.92 

Total  expense  

$20.55 

$17.49 

$18.64 

RELATION  BETWEEN  SIZE  OF  HERD  AND  EXPENSE 
OF  MILKING  BY  HAND 

The  thirty-four  farms  where  the  cows  were  hand-milked  were  also 
divided  into  two  groups  according  to  the  size  of  the  herds.  In  Group 
I  were  nineteen  farms  with  a  total  of  350  cows  and  an  average  of 
18.4  cows  per  herd.  In  Group  II  were  fifteen  farms  with  a  total  of 
500  cows  and  an  average  of  33.3  cows  per  herd.  Table  11  shows  the 
average  amount  and  cost  of  man  labor  per  cow  in  each  of  the  two 
groups. 

TABLE  11. — RELATION  BETWEEN  SIZE  OF  HERD  AND  THE  AMOUNT  AND  COST  OF 
MAN  LABOR  USED  IN  CARING  FOR  Cows  MILKED  BY  HAND 


Group  I 

Group  II 

All  herds 

Number  of  cows  in  herd  

Less  than  25 

25  or  more 

Number  of  herds  

"  19 

15 

34 

Total  number  of  cows  

350 

500 

850 

Annual  number  of  hours  per  cow  .  .  . 
Annual  cost  per  cow  

135.9 

$23  .  78 

132.5 
$23.19 

133.9 
$23.44 

Altho  in  this  study  slightly  less  time  was  required  per  cow  in  the 
larger  herds  than  in  the  smaller,  the  difference  has  no  significance. 
This  is  shown  by  the  distribution  of  individual  records  (Table  13) 
based  on  the  hours  of  labor  per  cow.  There  is  no  evidence  from  these 
data  of  any  relation  between  the  size  of  the  herd  and  the  amount  of 
labor  required  per  cow  in  caring  for  cows  milked  by  hand. 


504 


BULLETIN  No.  241 


[January, 


COMPARATIVE  EXPENSE  OF  MECHANICAL  AND  HAND 
MILKING  IN  HERDS  OF  DIFFERENT  SIZES 

Table  12  shows  the  relative  amount  of  labor  and  the  comparative 
expense  of  mechanical  and  hand  milking  in  herds  having  less  than  25 
cows  and  in  those  having  25  cows  or  more.  In  this  study,  the  use  of 
mechanical  milkers  resulted  in  an  average  annual  saving  of  50.5 
hours  of  man  labor  per  cow  in  the  smaller  herds  and  of  53.4  hours 
in  the  larger  herds.  Table  13  shows  that  altho  there  was  considerable 
variation  among  the  individual  herds  in  regard  to  the  labor  require- 
ment per  cow,  the  saving  in  labor  resulting  from  the  use  of  mechanical 
milkers  was  marked. 


TABLE  12. — COMPARATIVE  EXPENSE  OF  MECHANICAL  AND  HAND  MILKING  IN 
HERDS  OF  DIFFERENT  SIZE 


Group 

Number  of 
cows  in 
herd 

Number  of 
herds 

Average 
number  of 
cows  in 
herd 

Hours  of 
labor 
per  cow 

Annual 
expense 
per  cow 

M. 
milk 

H. 

milk 

M. 
milk 

H. 
milk 

M. 

milk 

H. 

milk 

M. 
milk 

H. 

milk 

I.. 

Less  than  25 
25  or  more 

17 
15 
32 

19 
15 
34 

19.1 
35.7 
26.9 

18.4 
33.3 
25.0 

85.4 
79.1 
81.5 

135.9 
132.5 
133.9 

$20.55 
17.49 
18.64 

$23.78 
23.19 
23.44 

II  

All  herds.  . 

TABLE  13. — SHOWING  How  THE  AMOUNT  OF  MAN  LABOR  USED  IN  CARING  FOR 
ONE  Cow  FOR  ONE  YEAR  VARIED  ON  THE  DIFFERENT  FARMS 


Number  of  herds 


Hours  per  cow 

Group  I 
Less  than  25  cows 

Group  II 
25  cows  or  more 

All  herds 

Mech. 
milk 

Hand 
milk 

Mech. 
milk 

Hand 
milk 

Mech. 
milk 

Hand 
milk 

50—  59.9.. 

i 

5 
'2 
3 
2 

2 
4 

3 
3 
2 
3 

4 

2 
4 
3 

'2 
1 
3 

3 
4 
3 
10 
9 
3 

-3 
9 
5 
3 

4 
3 

7 

60—  69  9  

1 
1 
7 
5 
3 

70—  79  9  

80—  89.9  

90—  99.9  

100—109  9  

110—119  9  

120—129  9..  

130—139.9  

140—149.9  

150—159.9  

160—169.9  

Total.  . 

17 

19 

15 

15 

32 

34 

The  annual  saving  in  expense  resulting  from  mechanical  milking 
averaged  $3.23  per  cow  in  herds  of  less  than  25  cows  and  $5.70  per 
cow  in  herds  of  25  cows  or  more.  This  saving  was  based  upon  the 
average  labor  rate  (17.5  cents)  on  all  farms  involved  in  this  investiga- 


COMPARISON  OF  MECHANICAL  AND  HAND  MILKING 


505 


lion.  What  the  difference  between  the  expense  of  mechanical  milking 
and  that  of  hand  milking  on  the  farms  involved  in  the  present  study 
would  have  been  if  other  rates  for  labor  had  been  used  is  indicated 
by  Table  14.  The  difference  in  expense  in  the  group  of  farms  having 
herds  of  less  than  25  cows  would  have  ranged  from  $.46  per  cow  with 
labor  at  12  cents  per  hour  to  $9.55  per  cow  with  labor  at  30  cents 
per  hour.  The  difference  in  expense  is,  of  course,  greater  in  the 
herds  having  more  than  25  cows  and  amounts  to  $12.37  per  cow  per 
annum  with  labor  at  30  cents  per  hour. 

TABLE   14. — COMPARISON  OF  DIFFERENCE  IN  EXPENSE  BETWEEN  HAND  AND 

MECHANICAL  MILKING  ON  THE  FARMS  INVOLVED  IN  THE  PRESENT 

STUDY  WHEN  VARIOUS  LABOR  RATES  ARE  USED 


Labor  rate 

Saving  in  expense  per  cow 

Group  I 
Herds  of  less 
than  25  cows 

Group  II 
Herds  of  25  cows 
or  more 

$     12.  . 

$  .46 
.97 
1.47 
1.97 
2.48 
2.98 
3.49 
3.99 
4.50 
5.01 
5.51 
6.02 
6.52 
7.03 
7.53 
8.03 
8.54 
9.04 
9.55 

$2.76 
3.29 
3.83 
4.36 
4.89 
5.42 
5.95 
6.50 
7.03 
7.56 
8.10 
8.64 
9.17 
9.70 
10.23 
10.77 
11.30 
11.83 
12.37 

.13  

.14  

.15  

.16  

.17  

.18  

.19  

.20  

.21  

.22  

.23  

.24  

.25  

.26  

.27  

.28  

.29  

.30  

These  data  indicate  that  the  cost  of  labor  is  the  principal  factor 
determining  the  relative  economy  of .  mechanical  and  hand  milking. 

CONCLUSIONS 

The  data  obtained  from  this  study  indicate  that  considerably  less 
labor  is  required  in  caring  for  cows  milked  mechanically  than  is 
required  in  caring  for  cows  milked  by  hand.  The  average  saving  of 
labor  on  the  farms  studied  was  approximately  40  percent.  This  saving 
of  labor  appears  to  be  greater  in  large  herds  than  in  small  herds,  but 
in  view  of  the  small  number  of  farms  studied  the  difference  found 
between  herds  of  different  sizes  was  too  slight  to  be  conclusive. 

The  cost  of  maintaining  and  operating  the  mechanical  milkers  off- 
sets to  some  extent  the  saving  in  labor  expense.  Hence  the  relative 
economy  of  hand  and  mechanical  milking  is  largely  determined  by  the 


506  BULLETIN  No.  241 

rate  paid  for  labor.  As  the  labor  rate  increases,  the  advantage  accrues 
more  and  more  to  mechanical  milking.  For  example:  the  average 
saving  in  expense  per  herd  of  36  cows  in  the  present  study  would 
have  been  $156.96  with  the  labor  cost  computed  at  15  cents  per  hour, 
or  $349.20  with  labor  at  25  cents  per  hour. 

Because  of  certain  fixed  costs  in  mechanical  milking,  the  expense 
per  cow  for  power  and  milkers  decreases  as  the  size  of  the  herd  in- 
creases. It  may  therefore  be  concluded  that  the  use  of  mechanical 
milkers  is  more  economical  in  large  herds  than  in  small  when  labor 
rates  and  other  factors  are  equal.  However,  a  dairyman  who  has 
a  small  herd  and  is  paying  a  high  price  for  labor,  may  find  mechanical 
milking  more  economical  than  would  a  dairyman  who  has  a  large 
herd  and  is  paying  a  lower  rate  for  labor. 

,  i1 

SOME  PUBLICATIONS  ON  MECHANICAL  MILKING 

1.  BRIGHT,  J.  W.     Milking  machines:    V,   The  production  of  high  grade  milk 
with  milking  machines  under  farm  conditions.     N.  Y.    (Geneva)   Agr.  Exp. 
Sta.  Bui.  472.     1920. 

2.  HUMPHREY,   H.    N.     Labor   requirements    of   dairy   farms    as    influenced    by 
milking  machines.     U.  S.  D.  A.    Bui.  423.    1916. 

3.  REUH.LE,  G.  L.  A.,  BREED,  R.  S.,  AND  SMITH,  G.  A.     Milking  machines:    III, 
As  a  source  of  bacteria  in  milk.     IV,  Methods  of  maintaining  in  a  bacteria- 
free  condition.     N.  Y.   (Geneva)   Agr.  Exp.  Sta.  Bui.  450.     1918. 

4.  EIDDELL,  F.  T.     Machine  vs.  hand  milking.    Mich.  Agr.  Col.  Exp.  Sta.    Quart. 
Bui.  1,  No.  4.     1919. 

5.  SMITH,  G.  A.,  AND  HARDING,  H.  A.     Milking  machines:    Effect  of  machine 
method  of  milking  upon  the  milk  flow.     N.  Y.   (Geneva)  Agr.  Exp.  Sta.  Bui. 
353.     1912. 

6.  WOLL,   F.  W.     Investigations   with   milking  machines.     Cal.  Agr.   Exp.   Sta. 
Bui.  311.    1919. 


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UNIVERSITY  OF  ILLINOIS-URBANA 


